Latin American and Caribbean countries experience energy transitions in the context of crises affecting power electric systems. This article shows that policy failure recognition constitutes a window of opportunity for regulatory reforms supporting the diffusion of renewable energy. This argument is illustrated with the cases of Mexico and Chile, both of which are regional leaders in renewable energy after policy reforms. In both cases, policy failures were key drivers of energy transition since they mobilised different actors in the pursuit of policy changes. However, policy responses depended on how different policy failures were interpreted as the origins and solutions to perceived energy crises. This study distinguishes between critical and ordinary policy failures. In the case of a critical failure, dominant policy ideas are placed under contest; whereas, in an ordinary policy failure, the normative underpinning of the policy remains valid, and it fails only in implementation. Because policy change in the energy sector is incremental, reactions to failures lead to a policy bricolage combining novel and older policy goals and instruments. This process shifts the balance in the prioritisation of the energy trilemma components (energy equity, security of supply, and environmental sustainability).